Valve system for cannula assembly

ABSTRACT

Valve assembly for sealed reception of an elongated object includes a valve body having at least one opening configured and dimensioned to permit entry of an elongated object and defining a central longitudinal axis, an elongated seal member formed of a resilient material and defining an aperture in general alignment with the opening of the valve body whereby the aperture is configured and dimensioned such that insertion of the object into the aperture causes the resilient material defining the aperture to resiliently engage the outer surface of the object in a substantially fluid flight manner, and at least one elongated guard member disposed within the seal member in supporting contact with the inner surface thereof. The guard member is positioned to engage the elongated object upon at least partial insertion of the elongated object into the valve body. The guard member includes at least a first substantially rigid portion adapted to be displaced relative to the longitudinal axis to facilitate expansion of the aperture of the seal member upon entry of the object therein and a second portion having less rigidity than the first portion of the guard member to enhance passage of the elongated object through the valve body.

This is a continuation of U.S. application Ser. No. 08/287,395, filedAug. 8, 1994, now U.S. Pat. No. 5,603,702.

BACKGROUND

1. Technical Field

The present disclosure relates to valve systems of the type adapted toallow the introduction of a surgical instrument into a patient's body.In particular, the disclosure relates to a valve system to be used incombination with a cannula where the cannula is intended for insertioninto a patient's body and an instrument is inserted into the patient'sbody through the cannula.

2. Background Of Related Art

Laparoscopic procedures are performed in the interior of the abdomenthrough a small incision, e.g., through narrow endoscopic tubes orcannulas inserted through a small entrance incision in the skin.Minimally invasive procedures are performed elsewhere in the body, e.g.,in the chest, and are often generally referred to as "endoscopic"procedures. Minimally invasive or endoscopic procedures generallyrequire that any instrumentation inserted into the body be sealed, i.e.provisions must be made to ensure that gases do not enter or exit thebody through the endoscopic incision as, for example, in surgicalprocedures in which the surgical region is insufflated. Moreover,endoscopic procedures often require the surgeon to act on organs,tissues, and vessels far removed from the incision, thereby requiringthat any instruments used in such procedures be relatively long andnarrow.

For such procedures, the introduction of a tube into certain anatomicalcavities such as the abdominal cavity is usually accomplished by use ofa system incorporating a trocar and cannula assembly. A cannula assemblyis formed of a cannula attached to a cannula housing which generallyincludes valve assembly adapted to maintain a seal across the opening ofthe valve assembly both with and without an instrument insertedtherethrough. Since the cannula is in direct communication with theinternal portion of the valve assembly, insertion of the cannula into anopening in the patient's body so as to reach the inner abdominal cavityshould be adapted to maintain a fluid tight interface between theabdominal cavity and the outside atmosphere.

Since minimally invasive surgical procedures in the abdominal cavity ofthe body generally require insufflating gases to raise the cavity wallaway from vital organs, the procedure is usually initiated by use of aVerres needle through which a gas is introduced into the body cavity.The gas provides a slight pressure which raises the wall surface of theperitoneum away from the vital organs thereby providing an adequateregion in which to operate. Thereafter, a trocar assembly which includesa cannula and a trocar or obturator is inserted within the cannula topuncture the peritoneum, i.e. the inner lining of the abdominal cavitywall. The obturator is removed and laparoscopic or endoscopic surgicalinstruments may then be inserted through the cannula to perform surgerywithin the abdominal cavity. The cannula may also be utilized forintroducing tubes into the body as for drainage purposes, for specimenremoval, for diagnostic evaluations, or the like.

In view of the need to maintain the atmospheric integrity of the innerarea of the cavity, a valve assembly for a cannula which permitsintroduction of an obturator and a wide range of surgical instrumentsand which maintains the atmospheric integrity of the inner area of thecavity is desirable. Generally, in the context of insufflatory,minimally invasive surgical procedures, cannula assemblies includestructure(s) that two sealing requirements. The first requirement is toprovide a substantially fluid tight seal when an instrument is notpresent in the cannula. The second requirement is to provide asubstantially fluid tight seal when an instrument is being introducedinto or already is present in the cannula. In this regard, there havebeen a number of attempts in the prior art to provide such sealingrequirements.

U.S. Pat. No. 4,655,752 to Honkanen et al. teaches a cannula including ahousing and first and second seal members. The first seal member isconically tapered toward the bottom of the housing and has a circularopening in its center, while the second seal is conically tapered andcup shaped. The second seal includes at least one slit to allow for thepassage of instruments.

U.S. Pat. No. 4,929,235 to Merry et al. teaches a self-sealing catheterintroducer having a sealing mechanism to prevent blood or fluid leakage.The sealing mechanism includes a planar sealing element having a slitand a conical sealing element. The sealing elements are each adapted tosurround a tube.

U.S. Pat. Nos. 4,874,377 and 5,064,416 to Newgard et al. relate to aself-occluding intravascular cannula assembly in which an elastomericvalving member is positioned transversely to a housing and isperipherally compressed to cause displacement, distortion and/orTheological flow of the elastomeric material. A frustoconical dilatorprojection cooperates with the elastomeric valving member in moving thevalving member to a non-occluding position.

U.S. Pat. No. 5,300,033 to Miller suggests a valve constructionincluding an elastic body having a cylindrical wall with first andsecond walls formed integrally with the cylindrical wall. The secondwall includes a slit to permit passage of a surgical instrument andfirst and second leaflets which define the slit. The leaflets arethicker in cross section to provide an additional closing force at theslit.

Cannula assemblies have also been developed with a series of resilientsealing elements having a central aperture, e.g., commonly assignedapplication Ser. Nos. 07/874.291, filed Apr. 24,1992 and 07/873,416,filed Apr. 24, 1992. Upon insertion of an instrument, the sealingelements resiliently receive and form a seal about the instrument. Uponwithdrawal of the instrument, a fluid tight seal is provided by theinternal sealing elements.

A disadvantage of several known valve systems for cannulas concerns thedifficulty encountered in inserting and advancing the surgicalinstrument through the valve unit. In particular, since knownelastomeric seal members are designed to form and maintain a fluid tightseal about the instrument, the aperture or slit within the seal throughwhich the instrument is passed is of relatively small or narrowdimension. Further, portions of the valve member defining the apertureare generally thick in cross-section to provide a sufficient closingforce of the seal about the instrument. see, e.g., U.S. Pat. No.5,300,033. As a consequence of these design considerations, the level offorce needed to insert and advance the instrument through the sealaperture is increased, thereby requiring awkward maneuvering on thesurgeon's behalf to appropriately position the instrument for thedesired surgery. Moreover, known valve systems are generally ineffectualin accommodating instruments of differing diameter while maintainingacceptable insertion forces and facilitating the range of desiredsurgical manipulations, e.g., angular instrument movements and specimenremoval.

Accordingly, the present invention obviates the disadvantages of theprior art by providing a valve unit or assembly for a cannula assembly,which is capable of forming and maintaining a tight seal aboutinstruments of varying diameters inserted through the cannula and whichincorporates structure to enhance and facilitate passage of theinstrument through the valve unit.

SUMMARY

Generally stated, the present disclosure is directed to a valve assemblyfor sealed reception of an elongated object. The assembly includes avalve body having at least one opening configured and dimensioned topermit entry of an elongated object and defining a central longitudinalaxis, an elongated seal member formed of a resilient material anddefining an aperture in general alignment with the opening of the valvebody whereby the aperture is configured and dimensioned such thatinsertion of the object into the aperture causes the resilient materialdefining the aperture to resiliently engage the outer surface of theobject in a substantially fluid tight manner, and at least one elongatedguard member disposed within the valve member in supporting contact withthe inner surface thereof and positioned to engage the elongated objectupon at least partial insertion of the elongated object into the valvebody. The guard member includes at least a first substantially rigidportion adapted to be displaced relative to the longitudinal axis tofacilitate expansion of the aperture of the seal member and a secondportion having less rigidity than the first portion of the guard memberto enhance passage of the elongated object through the valve body. Thesecond portion of the guard member may be positioned adjacent theaperture of the seal member to provide an interface between the guardmember and the seal member to thereby protect the portions of the sealmember defining the aperture from engagement with the elongated object.

The preferred guard member is a monolithically formed single piece unitwherein the first portion of the guard member defines a cross-sectionaldimension which is greater than the cross-sectional dimension of thesecond portion, thus providing the more rigid characteristic to thefirst portion.

In a preferred embodiment, the valve assembly includes a valve housinghaving a longitudinal opening configured and dimensioned to permit entryof an elongated object, an elongated resilient seal member at leastpartially positionable within the valve housing and defining an apertureto permit entry of the elongated object therein in a substantially fluidtight manner and a plurality of guard members disposed within the sealmember and concentrically arranged about a central longitudinal axisdefined by the valve housing. The plurality of guard members arepositioned to engage the elongated object upon insertion of theelongated object within the valve housing and are adapted to be radiallydisplaced upon introduction of the elongated object to engage portionsof the seal member defining the aperture to expand the aperture. Eachguard member possesses an end portion of less rigidity than theremaining portion(s) of the guard member wherein the end portion of lessrigidity reduces the force required to advance the elongated objectthrough the valve housing.

The guard members of this embodiment are preferably pivotally mounted toa generally annular guard mount and extend generally longitudinallywithin the seal member. The end portions of the guard members overlap toform an iris-like arrangement. Upon entry of the elongated object, theguard members simultaneously pivot outwardly to uniformly engage andstretch or dilate the inner surfaces of the seal member to open orexpand the aperture.

The elongated seal member of the valve assembly preferably includes acentral frusto-conical portion which accommodates the guard members anda circumferential portion. The circumferential portion includes abellows structure which is engageable with the valve housing anddimensioned to maintain a substantially fluid tight seal with the valvehousing upon manipulation of the elongated object within the aperture.In particular, the bellows structure enables the seal member to floatwithin the valve housing while maintaining a fluid tight seal about theelongated object and within the housing.

The valve assembly is intended to be used in combination with a cannulaincluding a cannula housing and a cannula sleeve extending distally fromthe cannula housing and is preferably detachably connectable to thecannula housing. The cannula housing may include a valve member disposedtherein which is moveable between a substantially closed position in theabsence of an instrument to an open position in the presence of aninstrument.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments are described hereinbelow with reference to thedrawings wherein:

FIG. 1 is a perspective view with parts separated of a trocar assemblycannula assembly and valve assembly constructed according to theprinciples of the present disclosure;

FIG. 2A is an exploded perspective view with parts separated of thevalve assembly of FIG. 1;

FIG. 2B is a perspective view of the valve assembly in the assembledcondition;

FIG. 3 is an enlarged perspective view of the resilient seal member ofthe valve assembly of FIG. 2A;

FIG. 4 is a cross-sectional view of the seal member of FIG. 3;

FIG. 5 is an enlarged perspective view of the guard mount of the valveassembly of FIG. 2A illustrating the guard members supported by theguard mount;

FIG. 6 is a top plan view of the guard mount of FIG. 5 with the guardelements disassembled from the guard mount;

FIG. 7 is a cross-sectional view taken along the lines 7--7 of FIG. 6;

FIGS. 8A-8C are cross-sectional views of a portion of a single guardmount illustrating a preferred method for pivotally connecting a guardelement to the guard mount;

FIG. 9 is an alternative two-piece guard mount to be incorporated in thevalve assembly of FIG. 2A and illustrates a preferred method formounting the guard elements to the guard mount;

FIG. 10 is a side plan view in partial cross-section of the cannulahousing and the valve assembly detachably mounted the cannula housing ofthe cannula assembly;

FIG. 11 is an enlarged cross-sectional view illustrating the valveassembly and the cannula housing;

FIG. 12 is a view similar to FIG. 10 illustrating the introduction of anelongated object into the valve assembly and cannula assembly;

FIG. 13 is a view similar to FIG. 11 illustrating sealing engagement ofthe resilient seal member of the valve assembly with the elongatedobject;

FIG. 14 is a view similar to FIG. 12 illustrating the adaptability ofthe valve assembly to radial movement of the elongated object in thecannula assembly;

FIG. 15 is a view similar to FIG. 13 further depicting the adaptabilityof the valve assembly to accommodate for radial movement of theelongated member;

FIG. 16 is a side plan view in partial cross-section of an assembledtrocar and cannula assembly in combination with the valve assembly ofFIG. 2A;

FIG. 17 is an enlarged isolated view of the mechanism for detachablysecuring the trocar assembly relative to the valve assembly;

FIG. 18 is an enlarged perspective view of an alternative guard mount tobe incorporated in the valve assembly of FIG. 2A;

FIG. 19 is an enlarged perspective view of a single guard element of theguard mount of FIG. 18 illustrating the mounting of the guard element tothe guard mount; and

FIG. 20 is a cross-sectional view of the valve assembly with the guardmount of FIG. 18.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S)

The present disclosure contemplates the introduction into a person'sbody of all types of surgical instruments including clip appliers,graspers, dissectors, retractors, staplers, laser fibers, photographicdevices, endoscopes and laparoscopes, tubes, and the like. All suchobjects are referred to herein as "instruments".

Referring initially to FIG. 1, there is illustrated the novel valveassembly 100 constructed in accordance with the principles of thepresent disclosure and intended to be used in combination with aconventional trocar assembly consisting of cannula assembly 200 andtrocar 300.

The valve assembly of the present disclosure, either alone or incombination with a valve unit/seal assembly internal to cannula assembly200, and either integral with or detachably mounted to cannula assembly200, provides a substantial seal between a body cavity of a patient andthe outside atmosphere, both, during and subsequent to insertion of aninstrument through the cannula. Moreover, the valve assembly 100 of thepresent disclosure is capable of accommodating instruments of varyingdiameter, e.g. from 5 mm to 12 mm, by providing a gas tight seal witheach instrument when inserted. The flexibility of the present valveassembly greatly facilitates endoscopic surgery where a variety ofinstruments having differing diameters are often needed during a singlesurgical procedure.

The valve assembly is preferably detachably mountable to the proximalend of cannula assembly 200 disclosed herein. Thus, the surgeon canremove the valve assembly 100 from the cannula assembly 200 at any timeduring the surgical procedure and, similarly, mount the assembly 100 tothe cannula when desired to provide a sealing engagement with aninstrument to be inserted through the cannula assembly. In addition, thevalve assembly 100 may be readily adapted to be mounted to conventionalcannulas assemblies of differing structures. The detachability of valveassembly 100 from cannula assembly 200 facilitates specimen removalthrough cannula assembly 200 and reduces the profile of cannula assembly200 when valve assembly is not needed for the surgical procedure.

Referring now to FIGS. 2A and 2B, the novel valve assembly of thepresent disclosure will be discussed in detail. As shown in the explodedview of FIG. 2A, Valve assembly 100 includes end cap 102, stabilizerplate 104, guard mount 106, guard holder 108, seal element 110 and sealhousing 112. End cap 102, stabilizer plate 104 and seal housing 112 formthe outer valve body of the assembly, which houses the sealing anddilating components of the system, i.e., guard mount 106, guard holder108 and seal element 110.

End cap 102 is generally cylindrically-shaped and includes a proximalend portion 103 defining a diameter which is less than the diameter ofthe remaining portion of the end cap and an inner peripheral ledge 114which supports stabilizer plate 104. Guard holder 108 is ring-like inconfiguration and includes inner and outer peripheral grooves 109, 111respectively formed in its proximal face. Grooves 109, 111 assist inretaining guard mount 106 within seal 110. Seal housing 112 includescentral opening 116, a proximal cylindrical portion 118 and a distalouter flange 120 having a scalloped surface to facilitate handlingthereof. Cylindrical portion 118 is received within end cap 102 when thevalve assembly is fully assembled to enclose the sealing components. Thedistal end face of seal housing 112 includes a peripheral groove 122 andtwo opposed rib portions 124 extending radially inwardly adjacent thegroove 122. Groove 122 and rib portions 124 assist in mounting valveassembly 100 to cannula assembly 200 as will be appreciated from thedescription provided below. The distal end face of seal housing 112 alsoincludes a second groove 126 adjacent opening 116 for accommodating aportion of seal 110.

Referring now to FIGS. 2A, 3 and 4, sealing element 110 includes agenerally frusto-conical interior portion 128 defining aperture 130, acircumferential flange portion 132 at its proximal end andcircumferential bellows structure 134 disposed adjacent the distal endof the seal 110 and having distal outer flange portion 135. Seal 110 isfabricated from an elastomeric material such as synthetic or naturalrubber which is preferably sufficiently resilient to accommodate andprovide a fluid seal with instruments of varying diameters insertedthrough aperture 130, e.g., instruments ranging in diameter from about 5mm to about 12 mm, and sufficiently resilient to flex at bellowsstructure 134 to accommodate manipulation of instrumentation insertedthrough aperture 130. A plurality of generally longitudinally extendingribs 136 are disposed along the inner surface of frusto-conical portion128. Ribs 136 provide additional support to seal 110 and are intended toengage the elongated instrument upon insertion thereof through the sealto minimize the potential of damage such as cutting or tearing of theseal by the distal end of the instrument. Flanges 132, 135 function inmounting seal 110 to the valve body as will be appreciated from thefollowing description. Seal 110 may also include at least one aligningprojection 133 extending from its proximal face to assist in mountingthe seal to guard mount 106. Preferably seal 110 includes threeprojections 133.

Referring now to FIG. 2A, in conjunction with FIGS. 5-7, guard mount 106of valve assembly 100 will be discussed. Guard mount 106 includes anannular base portion 138 and a plurality of guard elements 140 pivotallymounted relative to the base portion. Base portion 138 defines a centralopening 142 which is variably dimensioned to permit passage of aninstrument therethrough, as discussed below, and an outercircumferential flange 144 at its proximal end. Circumferential flange144 includes a circumferential lip 147 and three apertures 145correspondingly dimensioned to accommodate the three aligningprojections 133 extending from seal 110 (FIG. 2A).

Guard mount 106 also includes a plurality of slots 146 (FIG. 6) definedin the outer wall of base portion 138 for accommodating the proximalends of guard elements 140. Slots 146 are equidistantly disposed aboutbase portion 138 and extend generally longitudinally from a positionintermediate the proximal and distal ends of the guard mount 106 throughthe distal end face of the base portion 138.

Each guard element 140 includes a finger-like portion 148 and an outerflap portion 150 connected at distal end of finger portion 148. Flapportion 150 may be joined to finger portion 148 in a variety of manners,e.g., adhesive or insert molding, or flap portion 150 and finger portion148 may preferably be an integrally molded component. Finger portions148 are accommodated within respective slots 146 in guard mount 106 andinclude a pair of opposed projecting members 152 extending outwardlyfrom their proximal ends (FIG. 6). Projecting members 152 serve inpivotally mounting guard elements 140 to guard mount 106.

As best shown in FIGS. 7 and 8A-8C, the outer flap 150 of each guardelement 140 defines first and second portions 154, 156 of varyingthicknesses. The first or proximal portion 154 has a cross-sectionaldimension or thickness which is greater than the thickness of the secondor distal portion 156 of the outer flap 150. Preferably, first portion154 is from about two to about three times thicker in cross-sectionaldimension than second portion 156. This dimensional ratio translates tosecond portion 156 being about two to three times more flexible thanfirst portion 154, assuming the same material of construction. Suchdimensioning of outer flap 150 ensures that guard elements 140 aresufficiently rigid to cause stretching surface of the seal surfaceportions 110 defining seal aperture 130 to thereby increase thedimension of the aperture 130 and facilitate insertion of the instrumenttherethrough and, in addition, provide sufficient flexibility tominimize the force required to advance the instrument through the guardelement and seal arrangement.

More specifically, by the strategic dimensioning of the guard elements140 the following characteristics are present: 1) the finger portion 148in combination with the relative thick first portion 154 of outer flap150 provides a substantially rigid section of the guard element 140,which section is capable of sufficiently engaging the innerfrustoconical surface 128 of seal 110 and enlarging the aperture 130 ofthe seal by displacing seal portions defining the aperture 130 radiallyoutwardly; and 2) the relatively thin and less rigid, second portion 156of outer flap 150 reduces the force required to pass the instrumentthrough the guard mount and seal arrangement and, also, minimizes therisk of damage to the inner surface of the seal by providing aprotective interface between the instrument and the inner wall. Inasmuchas guard elements 140 are pivotally mounted to guard mount 106, as aninstrument contacts outer flap 150 along its length, i.e., both alongfirst portion 154 and second portion 156, outer flap 150 is pivotedrelative to projecting members 152 against seal 110 in dilating contacttherewith.

Guard elements are fabricated from a suitable material such as highdensity polyethylene, and, as noted above, are preferably monolithicallyformed by injection molding techniques to define a single element. It isalso possible for the finger portion 148 and flap portion 150 of guardelement 140 to be individually formed and subsequently connected byadhesives or the like.

Referring now to FIGS. 6, 7, and 8A-8C, the mounting of each guardelement 140 to guard mount 106 will be discussed in detail. Each guardelement 140 is individually mounted within a slot 146 in base portion138 of guard mount 106 by inserting the proximal finger portion 148within the base of the slot as shown in FIG. 8A and advancing the guardelement into the slot such that the opposed projecting members 152 snapinto correspondingly dimensioned grooves 158 (FIGS. 8A-8C) formed inportions 160 of base 138 adjacent each slot.(see FIG. 6) FIG. 8B depictsthe projecting members 152 locked into grooves 158. Thereafter, eachguard element 140 is pivoted upwardly to its appropriate position asshown in FIG. 8C.

FIG. 9 illustrates an alternative guard mount 162, and assembly methodtherefor, to be incorporated in the valve assembly 100 of the presentdisclosure. In accordance with this embodiment, guard mount 162 includeslower half section 164 and upper half section 166 positionable on thelower half section. Guard mount 162 is substantially identical inconfiguration to the guard mount 106 described in connection with FIGS.5-7 except that this guard mount 162 is provided with a radial groove168 which is disposed adjacent each slot 170. In further accordance withthis embodiment, the guard elements 140 are simultaneously integrallymolded to define a single unit as shown in FIG. 9. In the single moldedunit, each guard element 140 is appropriately positioned and oriented tobe placed within a corresponding slot 170 within the lower half section164 of guard mount 162, i.e., during assembly, the single unit ispositioned against the lower section 164 with guard elements 140 beingreceived within the slot portions 170. Thereafter, the central moldedportion 172 and the stems 174 interconnecting the guard elements 140 andthe central molded portion are removed leaving the guard elements 140within their respective slots. It is to be appreciated that a portion ofstem 174 connected to each guard element 140 may remain after removal ofthe central portion 172. This stem portion is received within radialgroove 168 in assembly and serves to resist any tendency of the guardelement 140 to rotate out of its respective slot 170. Once the guardelements 140 are positioned within their respective slots 170 with theopposed projections 152 in place within grooves 176 in guard mount 162,the upper section 166 of the guard mount is attached to the lowersection by adhesives, spot welding or the like. The assembled guardmount 160 and guard elements 140 operate in a similar manner to thatdescribed in connection with mount 106 of FIG. 5.

Referring again to FIG. 5, the guard elements 140 in their fullyassembled position may be oriented define a generally frusto-conicalconfiguration so as to be positioned within the frusto-conical portion128 of seal 110. Preferably, guard elements 140 are arranged inoverlapping relation, i.e., whereby outer flap portions 150 of adjacentguard elements 140 overlap each other to define a general iris-likearrangement of the guard elements. This desired arrangement is achievedby pivoting a first guard element 140 inwardly and thereaftersequentially pivoting the remaining guard elements onto each other. Onceall the guard elements 140 are in a fully pivoted position, the leadingedge of the outer flap portion 150 of the last pivoted guard element 140is tucked under the trailing edge of the flap portion 150 of the firstpivoted guard element to provide the arrangement shown in FIG. 5.

Referring now to FIGS. 2A-2B, in conjunction with FIGS. 10-11, theassembling of the components of valve assembly 100 will be discussed indetail. Although in FIGS. 10 and 11 the valve assembly 100 is shownalready mounted to cannula assembly 200, it is to be appreciated thatgenerally valve assembly 100 is first assembled as a single unit andthen mounted to the cannula assembly. The mounting of valve assembly 100to cannula assembly 200 will be discussed below. Stabilizer plate 104 ispositioned within end cap 102 such that the plate 104 rests on innerperipheral ledge 114 defined within the end cap 102. Thereafter, guardholder 108 is positioned over the proximal flange 132 (FIG. 4) of seal110 whereby the inner peripheral groove 109 of the guard holder 108receives and accommodates the proximal flange 132 of the seal 110.Thereafter, seal 110 and guard holder 108 are positioned over guardmount 106 (FIG. 5) and advanced onto the mount until proximal flange 132of the seal is abutting circumferential flange 144 of the mount 106 andaligning projections 133 are received within apertures 145 (FIG. 2A andFIG. 5) formed in the circumferential flange 144 as shown incross-section in FIG. 11. In this position, the circumferential lip 147on circumferential flange 144 (FIG. 5) is received within the outergroove 111 of guard holder 108.

Assembly is continued by placing the assembled seal 110, guard holder108 and guard mount 106 subassembly against stabilizer plate 104 whichis positioned against ledge 114 within end cap 102. Thereafter, sealhousing 112 is positioned over the entire unit with the cylindrical wall118 of the seal housing being received within the cylindrical wall ofend cap 102. In this assembled condition, the distal end portion of thecylindrical wall of end cap 102 is received within an annular spacedefined between distal flange 120 of seal housing 112 and cylindricalwall 118 of seal housing 112 and retained therein by a friction or snapfit, thus retaining the valve assembly in a fully assembled condition.It is to be noted that in the assembled condition the distal flange 135of bellows structure 134 of seal 110 is a positioned over the distalface of seal housing 112 wherein the flange 135 is received withinsecond circumferential groove 126 of the seal housing.

The valve assembly 100 now in its fully assembled condition can bemounted to cannula assembly 200. Referring to FIGS. 1, 10 and 11,cannula assembly 200 is part of a trocar assembly and includes a cannulasleeve 202 and a cannula housing 204 mounted on one end of the sleeve.Sleeve 202 defines a cannula passage in its interior and may be formedof stainless steel or other rigid materials such as polymeric materialsor the like.

Cannula housing 204 is rigidly secured to the proximal end of cannula202 and defines a longitudinal opening for reception and passage of anelongated surgical instrument. The proximal end portion of the cannulahousing 204 defines a generally circular cross-section and possessesdiametrically opposed leg portions 206. A cannula seal 208 fabricatedfrom a resilient material, e.g., rubber, is positioned within theinterior of cannula housing 204. Seal 208 includes a circumferentialflange portion 210 which rests on a correspondingly dimensionedcircumferential ledge 212 within cannula housing 204. Seal 208 generallydefines a duck bill shape having two planar tapering portions 214 whichintersect at their distal ends to define abutment face 216. The planartapering portions 214 may each include one or more inwardly directed,longitudinally oriented ribs to facilitate instrument passage. Abutmentface 216 permits passage of the elongated object through the seal 208,but in the absence of an instrument, and particularly when cannula 202is inserted into an insufflated body cavity, abutment face 216 forms agas-tight seal that isolates the insufflated cavity from the ambientsurroundings. Seal 208 also includes at least one, preferably two,reinforcing ribs 215 to stabilize the seal. Ribs 215 are positioned toengage the instrument to guide the instrument through slits 216 andprevent piercing of the seal 208 by the tip of the instrument.

Cannula assembly 200 also includes a stabilizing plate 218 (FIG. 1)which is positioned against the flange portion 210 of seal 208 toprovide support for the seal during introduction and withdrawal of anelongated instrument. Stabilizing plate 218 includes two diametricallyopposed extensions 220 (FIG. 1) which are received within thecorrespondingly dimensioned leg portions 206 of the cannula housing 204.In the preferred embodiment, stabilizing plate 218 is securely attachedto cannula housing 204 at contact points along the extensions of therespective components by spot welding, adhesives or the like.Stabilizing plate 218 also includes a partial external annular rib orthread 222 (FIG. 11) adjacent its proximal end, the function of whichwill be appreciated from the description below.

A stop cock valve 224 may be incorporated as part of cannula housing 204to permit the passage of insufflation gases through the cannula and intothe body cavity. A suitable valve for this purpose is available from theBurron OEM Division of B. Braun Medical, Inc. (Model No. 55401022).

Referring still to FIGS. 1, 10 and 11, the mounting of valve assembly100 to cannula housing 204 will be discussed. The assembled valveassembly 100 is detachably mounted adjacent stabilizing plate 218 withthe partial annular thread 222 of the stabilizing plate 218 beingreceived within the peripheral groove 122 (FIG. 2a) defined in thedistal face of seal housing 112. The valve assembly 100 is rotated tocause engagement of the radially inwardly projecting rib portions 124adjacent groove 122 with the partial annular thread 222 to releasablylock the valve assembly 100 to the cannula housing. Other means fordetachably connecting the valve assembly 100 to cannula housing 204 canbe readily determined by one skilled in the art such as screw threads,adhesives, bayonet locking, and the like.

Referring now to FIGS. 12 and 13, an elongated object such as a surgicalinstrument, identified generally as numeral 400, may be inserted throughthe valve assembly 100 and into the cannula 200 to perform the desireddiagnostic procedure and/or surgery. As the surgical instrument entersthe valve assembly, the tip of the surgical instrument is engaged by theguard elements 140. Upon further advancement of the surgical instrument,the guard elements 140 are pivoted radially outwardly to bias the sealmember in an outward direction thereby stretching the seal portionsdefining the aperture 130 and increasing the dimension of the apertureto the degree necessary to accommodate instrument 400. As previouslystated, the particular dimensioning of the guard elements 140, i.e. therigid section in combination with the more flexible outer portion,ensures adequate stretching of the seal element 110 while alsopermitting relatively easy passage of instrument 400 through the valveassembly. In addition, the overlapping arrangement of the outer flapportions 150 of the guard elements facilitate dilation of the sealaperture and minimize the potential for the distal end of the instrumentto contact and pierce the resilient material of the inner surface ofseal 110 by providing an interface between the guard elements and theseal. The resilient seal member 110 sealingly engages to form asubstantial fluid-tight seal about the surgical instrument and a fluidtight seal within the valve housing and the external atmosphere. Theinstrument 400 is advanced through the cannula assembly 200 whereby theduckbill seal of the cannula assembly also spreads to allow passage ofthe instrument. Once positioned within the valve assembly 100 andcannula assembly 200, the surgical instrument may be maneuvered aboutthe internal body cavity.

As shown in FIGS. 14-15, the valve assembly permits limited unencumberedmovement of the instrument in a radial direction (relative to thecenterline of sleeve 202) while still maintaining an adequate seal aboutthe instrument. This is due to the strategic spacing of the inner valvecomponents, i.e., guard mount 106 and seal 110, relative to the valvebody, i.e., end cap 102 and seal housing 112, and the bellows structure134 of the seal 110. In particular, the bellows structure 134 providessufficient flexibility to permit the valve components to "float" withinthe valve housing while still preserving the integrity of the sealsestablished about the surgical instrument and within the cannulaassembly. Thus, manipulation of the instrument in any direction, eitherlongitudinally or radially, to he extent permitted by the rigid housingsand cannula, will not effect the seal, since the resilient material ofthe seal element and the bellows structure will conform to the movementsof the instrument and assume a desired shape necessary to retain sealingcontact with the instrument.

Referring now to FIGS. 1, 16 and 17, the novel valve assembly 100 may beused with a trocar of the type described in the figures. This trocar 300is disclosed in U.S. patent application. Ser. No. 07/957,673 filed Oct.7, 1992, now issued as U.S. Pat No. 5,356,241 the contents of which areincorporated herein by reference, and includes trocar housing 302, anobturator 304 extending distally from the housing 302 and havingpiercing tip 306 and a stationary or tube 308 which houses the obturatorwhen it is unarmed. Obturator 304 is advanced beyond the distal end ofsleeve 202 to expose the obturator tip 306 by advancing actuating button310. This trocar 300 also includes a locking hinge 312 within the trocarhousing 302 which is actuated upon depression of the actuating lever310.

The trocar housing 302 may be longitudinally fixed relative to valveassembly 100 and cannula 200 by inserting the trocar within the aperturedefined in end cap 102 of the assembly 100, advancing the trocar throughthe valve assembly and into cannula sleeve 202, and advancing actuatingbutton 310. The proximal end portion 103 of end cap 102 defines asmaller diameter than the remaining or main portion of the cap 102 (Seealso FIG. 11) and, thus, defines a circumferential locking ledge 105 atits intersection with the main cap portion. Once the trocar 300 isappropriately positioned in the cannula sleeve 202, the obturator 304and obturator tip 306 are advanced by advancing actuating button 310which causes corresponding radial outward movement of the hinge member312 and engagement of the hinge member 312 with the circumferentiallocking ledge 105 of the end cap 102 as shown in FIG. 17 to detachablysecure the trocar housing 302 relative to the valve assembly 100 andcannula assembly 200. Because locking ledge 105 extendscircumferentially, trocar housing 302 may be detachably secured to valveassembly 100 at any relative angular orientation. The valve assembly iscapable of forming a seal about the trocar in the same manner describedabove.

In operation, the distal end of the trocar 300 having the obturator tip306 in an exposed position beyond the sleeve 202 of the cannula assembly200 is placed against the skin at the body cavity region, and pressureis exerted on the assembly against the skin. This pressure causes theobturator tip 306 to enter the skin and underlying tissue. Once the tiphas penetrated the tissue and has entered the cavity, the tipautomatically retracts into the cannula as described in U.S. Pat. No.5,116,353, and the trocar can be withdrawn from the cannula assembly topermit introduction of surgical instruments such as forceps, graspers,or the like through the remaining cannula assembly 200. Alternatively, atrocar having a spring biased protective sleeve such as is described inU.S. Pat. No. 4,601,710 or a conventional trocar which does not includea safety mechanism may be employed through valve assembly 100 andcannula assembly 200. It is to be appreciated that upon removal of thetrocar 300 from the cannula assembly 200, the duck bill 208 closesautomatically to preserve the state of insufflation of the peritoneum.In particular, the pressure exerted by the insufflation gases throughthe cannula sleeve 202 biases the planar portions 214 (FIG. 14) of theduck bill 208 towards each other thereby closing the abutment face 216defined at the juncture of the two planar portions.

FIGS. 18-20 depict an alternate guard mount 180 to be incorporated inthe valve assembly of the present disclosure. In accordance with thisembodiment, the guard elements 182 are mounted to the guard mount viatwo rods 184 which are connected at their first ends to the guardelement 182 via insert molding techniques and at the second ends to apivot rod 186 within the guard mount. The guard elements 186 pivot in asimilar manner to that described in connection with the embodiment ofFIG. 1 and possess a rigid section as defined by the finger portion 188and a more flexible outer section as defined by outer flap 190.

While the above description contains many specifics, these specificsshould not be construed as limitations on the scope of the invention,but merely as an exemplification of a preferred embodiment thereof.Those skilled in the art will envision other possible variations thatare within the scope and spirit of the invention as defined by theclaims appended hereto.

What is claimed is:
 1. Valve assembly for sealed reception of anelongated object, which comprises:a) a valve body having at least oneopening configured and dimensioned to permit entry of an elongatedobject, and defining a central longitudinal axis; b) an elongated sealmember formed of a resilient material and defining an aperture ingeneral alignment with the opening of the valve body adapted toresiliently engage the outer surface of the object in a substantiallyfluid tight manner; and c) at least one elongated guard member disposedwithin the seal member and positioned to engage the elongated objectupon at least partial insertion of the elongated object into the valvebody, the guard member including at least a first substantially rigidportion and a second portion having less rigidity than the firstportion, the guard member adapted to be displaced relative to thelongitudinal axis such that at least the first substantially rigidmember engages inner surface portions of the seal member proximal of theaperture to thereby facilitate expansion of the aperture of the sealmember upon entry of the object therein.
 2. The valve assembly accordingto claim 1 wherein the at least one guard member includes a plurality ofguard members coaxially arranged about the central longitudinal axis. 3.The valve assembly according to claim 2 wherein the second portion ofadjacent guard members are disposed in partial overlapping relation. 4.The valve assembly according to claim 3 wherein the guard members aremounted for pivotal movement.
 5. The valve assembly according to claim 1wherein the at least one guard member is mounted for pivotal movementrelative to the longitudinal axis.
 6. A valve assembly for sealedreception of an elongated object, which comprises:(a) a valve housinghaving a longitudinal opening configured and dimensioned to permit entryof an elongate object; (b) an elongated resilient seal member at leastpartially positionable within the valve housing and defining an apertureto permit entry of the elongated object therein in at substantiallyfluid tight manner; and (c) a plurality of guard members disposed withinthe seal member and concentrically arranged about a central longitudinalaxis defined by the valve housing and positioned to engage the elongatedobject upon insertion of the elongated object within the valve housing,the guard members arranged such that at least end portions of adjacentguard members are in overlapping relation, each guard member adapted tobe radially displaced during introduction of the elongated object withinthe valve assembly to contact portions of the valve member adjacent, butproximal to, the aperture to facilitate passage of an elongated objecttherethrough, the end portions of the guard members being substantiallyflexible relative to the remaining portions of the guard members toeffectively minimize force required to advance the elongated objectthrough the guard members.
 7. The valve assembly according to claim 6,further including a guard mount, wherein each guard member is movablymounted to the guard mount.
 8. A valve assembly for sealed reception ofan elongated object, which comprises:(a) a valve housing having alongitudinal opening configured and dimensioned to permit entry of anelongated object; and (b) an elongated resilient seal member at leastpartially positionable within the valve housing, the seal memberincluding an inner portion and a peripheral portion, and defining acentral longitudinal axis, the inner portion defining a frusto conicalconfiguration and having an aperture in general alignment with thecentral longitudinal axis to permit entry of the elongated objecttherein in a substantially fluid tight manner, the peripheral portionincluding a bellows structure characterized by extending in alongitudinal direction, the bellows structure in coaxial arrangementabout at least a portion of the inner portion and being dimensioned tomaintain a substantially fluid tight seal with the valve housingnotwithstanding manipulation of the elongated object within the aperturein either a longitudinal or radial direction.
 9. A valve assembly forsealed reception of an elongated object, which comprises:(a) a valvehousing having a longitudinal opening configured and dimensioned topermit entry of an elongated object; (b) an elongated resilient sealmember at least partially positionable within the valve housing, theseal member including an inner portion and a peripheral portion, anddefining a central longitudinal axis, the inner portion defining afrusto conical configuration and having an aperture in general alignmentwith the central longitudinal axis to permit entry of the elongatedobject therein in a substantially fluid tight manner, the peripheralportion including a bellows structure characterized by extending in ageneral longitudinal direction, the bellows structure in coaxialarrangement about at least a portion of the inner portion and beingdimensioned to maintain a substantially fluid tight seal with the valvehousing notwithstanding manipulation of the elongated object within theaperture; and (c) at least two guard members disposed within the sealmember and positioned to engage the elongated object upon passagethrough the longitudinal opening of the valve housing, the guard membershaving rigid portions characterized by having sufficient rigidity toengage an inner surface portion of the seal member proximal of theaperture to facilitate expansion of the aperture upon passage of theelongated object.
 10. The valve assembly according to claim 9 includinga plurality of guard members wherein adjacent guard members are disposedin partial overlapping arrangement.